Aromatic polyimides have excellent heat resistance and mechanical properties, and are drawing attention as engineering plastics (see, for example, “Latest Polyimides: Basics and Applications” (2002) edited by Japan Polyimide & Aromatic Polymers Research Group). On the other hand, aromatic polyketones containing a carbonyl group in a main chain, such as aromatic polyimides, have excellent heat resistance and chemical resistance, and are also drawing attention as engineering plastics (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 2005-272728 and “Future Materials”, 2008, vol. 8, No. 8, page 42 to 47). Further, it is known that an aromatic polyketone having heat resistance and transparency can be obtained by introducing an alicyclic structure into an aromatic polyketone (see JP-A No. 2013-53194).
Demand for portable image display devices (mobile display devices), typified by mobile phones, is increasing in recent years, and lighter weight and improved reliability are required for optical elements included in the image display devices and the like. In response to such a demand, application of a polymer material (glass substitute material) and a surface protective layer (hard coat), which are capable of substituting glass and which have high transparency and are light weight, has been proposed (see, for example, JP-A No. 2013-156652).